Something for the wish list (not really a bug):
I was reminded of what I see as a problem with summary.glm last week when
some of my students fell into a trap in a homework exercise, defining a
logit model in which coefficients were aliased. When this happens in lm,
summary.lm prints a message ["Coefficients: (1 not defined because of
singularities)"], but summary.glm is silent. In both instances, the print
methods show aliased coefficients as NA.
At minimum, I think that it would be desirable for summary.glm to indicate
that there's a problem. In addition, I would prefer that both summary.glm
and summary.lm include aliased coefficients (as NA) in the table of
coefficients.
Thanks for your consideration,
John
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John Fox
Department of Sociology
McMaster University
Hamilton, Ontario, Canada L8S 4M4
email: jfox at mcmaster.ca
phone: 905-525-9140x23604
web: www.socsci.mcmaster.ca/jfox
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